The present invention relates to the textile industry and more particularly concerns a method and a device for forming a reserve of filling yarn for those looms wherein the filling is inserted into the shed without being carried by means reciprocating within said shed.
A number of looms make use of fluid means such as air or water jets to propel the filling through the shed. Another technique is known as "inertial insertion," and is described in particular in French Pat. No. 1,562,147 (corresponding to U.S. Pat. No. 3,543,808). This technique consists in propelling the filling of the form of a loop into the shed. One of the strands of said loop, termed the "propelled strand," has a free end and is propelled at high speed in a given direction, namely inside the shed formed by the gap between the warp yarns. The other strand, called the "slave strand" is kept in a tong outside the shed. In this manner the kinetic energy of the propelled strand is transformed in the loop into a force pulling the yarn in the direction of the loop motion. In every machine the filling yarn must be prepared in advance in the form of picks of which the length corresponds to the desired width and which are stored by a stocking means before being propelled into the shed.
Various techniques allow making such known yarn reserves. Some are called dynamic, for instance making use of a mobile member rotating about its axis in synchronization with the insertion frequency of the picks. This solution suffers from the major drawback that it requires a reliable and accurate control which must always be obtained by complex engineering and which is therefore quite expensive. Such a solution is described, for instance, in French Pat. No. 2,416,187.
Another technique, called static, is described in particular in French Pat. No. 1,581,247. The main drawback of the various embodiments of this technique is their very substantial bulk. An improvement in the static reserves is offered in French Pat. No. 2,162,944. Though the method and the device described in this document are appealing, their applicability as regards the means for propelling the pick into the shed is limited considering that the yarn necessarily must be extracted at the end opposite to its introduction.